The engineered bone marrow gives donor blood-forming stem cells a place to live without destroying the patient’s own bone marrow, said Shyni Varghese, a bioengineering professor at UCSD Jacobs School of Engineering. Because destruction of bone marrow knocks out the patient’s immune system, the interval until the donor cells take hold and begin functioning is highly dangerous.

The new technology could work in nonmalignant blood diseases, Varghese said. The donor cells would be immune-matched so they can coexist with the patient’s original blood-forming cells. It wouldn’t work in blood cancers, she said, because destruction of the patient’s bone marrow is required to eliminate the cancer cells.

The study was published Monday in PNAS. It can be found at j.mp/marrowbone. The engineered marrow-containing bone was implanted beneath the skin of mice, and experiments showed it functioned like regular bone marrow.

It will take more work before the animal study can be translated into something that can be tested in people, Varghese said. This study is a proof of concept that it should be feasible.

When asked how long it would take before the treatment was ready for clinical trials, Varghese chuckled.

“That is a question I always have a tough time answering,” she said. “We think it will be about five to 10 years.”

So far, the work has been entirely academic research, she said. But now it’s reasonable to look for a corporate partner that can take on commercializing the research.

The study can also serve as a tool to enable more research on blood formation, and how donor cells interact with the host, it said.

Researchers built the marrow using an artificial material matrix that provided space for marrow cells to lodge. This porous hydrogel structure was encased in a calcium phosphate matrix that supports bone cell formation. These implants, placed under the skin, matured into bone with a blood supply and marrow. The marrow contained both donor cells and the animal’s original blood-forming stem cells.

The researchers also took marrow cells from the implanted engineered marrow and transferred them into other mice that had their blood-forming stem cells destroyed with radiation and drugs. The transferred cells reconstituted the blood system in the mice.

The study was funded by the National Institutes of Health and the California Institute of Regenerative Medicine.